URBAN ROCKS: INVESTIGATING
STONE USED FOR BUILDINGS AND MONUMENTS
| Joseph T. Hannibal The Cleveland Museum of Natural History 1Wade Oval Drive, University Circle Cleveland, Ohio 44106-1767 |
Mark T. Schmidt American Geological Institute 4220 King Street Alexandria, Virginia 22302 |
Level: Second grade to senior high
Anticipated Learning Outcomes
Introduction
Our civilization is heavily dependent on geologic
materials for constructing roads, bridges, buildings, and monuments. Each
year, the U.S. consumption of geological materials is many tons per person
(Bates and Jackson, 1982). This includes a great amount of stone.
Stone used for building can be found in virtually any city or town, sometimes
in a great many varieties. Urban field trips focusing on building stone
have become quite popular in recent years. A number of geologists and educators
have fostered the use of building stone as an educational resource by leading
field trips and by publishing various materials, including guides to the
stone of various cities (e.g. Slagle, 1982) and descriptions of urban field
trips (e.g. Fazio, 1981; and Pennington and Mastie, 1984).
The concept of the urban field trip is now well established. Those who wish
to develop their own program in urban geology will find it very helpful
to read previous work on the topic such as the excellent articles by Fazio
and Nye (1980) and Fazio (1981). The field trip guidelines outlined below
are in many ways similar to those described in these works but the specifics
are based on our work with students in Cleveland (see also Hannibal and
Schmidt, in press).
Materials and Human Resources Needed
Background and Site Selection
In order to develop a successful unit utilizing
building stone one should have a background in geology. It may also be helpful
to obtain the aid of a geologist who is familiar with building materials.
Possible sites can include your school, the school's neighborhood, downtown,
shopping malls, cemeteries, or practically anywhere there are buildings
and monuments.
Downtown areas are particularly good places because guides to the building
stone used in a number of downtown areas are already available. Some of
the best guides are those by Hebrank (1989), Slagle (1982), and Wilson (1979).
If no guide is available for your city or town, or for the portion of the
city you are most interested in, you will need to do some investigating.
Instructions for "stone sleuthing" are given in Cvancara (1985,
chapter 22). Additional advice can be found in Fazio and Nye (1980), Fazio
(1981), and Hannibal and Schmidt (in press). One reasonably-priced work
that can aid in identification of building stone is Parsons (1990).
School buildings may be attractive sites, for there is no need for transportation.
Geological Focal Points
Organize your field trip as a series of stops.
Focal points at field trip stops could include a medium- to coarse-grained
granitic rock. The rock should be chosen carefully so that students will
be able to easily distinguish its mineral constituents. Students can sketch
and color the minerals in a portion of the stone (see worksheet). Locations
with granitic rocks of contrasting grain sizes can be used for discussion
of the relationship between grain size and rate of cooling. Also look for
igneous features such as flow banding and inclusions (xenoliths).
Comparative observations can be made at places where a single type of stone
has been treated in different ways. For example, most of the stone used
for a building may be polished, but some of the same type of stone may be
left unpolished.
Fossil-bearing limestones are excellent subjects of investigation (Fazio,
1981). One of the most commonly used building stones, known commercially
as Indiana limestone, is composed of fragments of sea lilies (crinoids and
blastoids), bryozoans, and other fossils. Trace fossils such as sinuous
trackways are also fairly common in this material. Worksheets with illustrations
of various fossils found in this stone can be prepared so that students
can circle types of fossils they observe.
Sedimentary features such as cross-beds in sandstone, and stylolites in
limestones, also can be examined.
Weathering of marble and limestone is another possible focal point of urban
field trips. Exposed outward-facing surfaces of exterior columns will roughen
due to weathering while inward-facing surfaces will be protected and remain
smooth. Have students feel the difference. Exterior sculptures and monuments
will lose their finely-carved details. (See Fazio and Nye, 1980, for additional
activities related to weathering.)
In order to help students make the connection between stone used for buildings
and natural rock outcrops it is useful to find information on locally quarried
building stone. If stone has been quarried in your area, find locations
where that stone has been used, and obtain natural samples or take photographs
of an outcrop of the rock for comparison.
Library research can reveal other useful information. With the help of standard
geological references one can find such information as the geologic age
of specific building stones and the formal geologic names of rock units
to which these stones belong.
Basic Preparation for the Field
Trip
Comments
Worksheets are necessary as they serve to focus attention at the various
stops. The worksheets will vary in complexity with the level of the student.
The sample worksheet included here was designed for investigation of a coarse-grained
granite at stop 1 and investigation of weathering of exterior marble columns
at stop 2. It is modified from worksheets we have used for classes of second-grade
students.
Pre-trip activities should introduce basic geologic concepts such as rock
classification and weathering. Be sure that the class knows about the general
types of stone that will be seen on the trip. Introduction can be through
lecture, reading, laboratory examination of stone, or other activities,
or, preferably a combination of these. Related activities could include
the use of crayons to model rock-forming processes (Birdd, 1990). If magnifying
devices are to be used on the field trip the students should be introduced
to their proper use before the field trip. It also is useful in many cases
to have students do a dry run of activities. For instance, if young students
will be drawing and coloring the minerals found in part of a building, they
might do the same for a hand sample of rock in the classroom as preparation.
The Field Trip
Take the class to the various stops and provide
a brief orientation at each location. Distribute worksheets and help the
students in filling out the worksheets. Depending on the level of the class,
the students may need some guidance in drawing, making observations, comparing
various materials, etc. Reading the material on the worksheets out loud
seems to help with younger students, especially when there is much variation
in reading level. Answers can be discussed in the field, with individual
students describing what they have seen. There will often be variation in
individual students' observations.
Follow-up
Discussion of observations made on the trip can
continue in the classroom. Slides taken at various stops can serve as useful
reminders of features examined during discussions. See Fazio (1981) for
additional follow-up activities.
Discussion and Conclusion
Urban field trips should acquaint students with
materials they have "seen" previously yet never really noticed.
The trips may also foster appreciation of buildings and other urban structures.
While urban field trips can be used as a self-contained unit on geology,
the study of building stone can also be combined with other disciplines
to form a multidisciplinary unit. Fazio (1981) has integrated mathematical
calculations into his program. Trips to classic downtown buildings can serve
as combined lessons in geology and architecture. Examination of sculptures
can combine lessons in geology and art. A field trip to one of the state
capitols, or other splendid public buildings built with a variety of building
stone, could include lessons in geology, architecture, history, and civics.
Acknowledgements
Our work with children has benefited from discussion
and interaction with Linda Zelazny and Ray Levi of University School, Shaker
Heights, Ohio, and participants in our "Field Geology for Teachers"
class.
References
Bates, R. L. and Jackson, J. A., 1982, Our Modern
Stone Age: Los Altos, William Kaufmann, 136 p.
Birdd, D. L., 1990, Rocks! rocks! rocks!, in Oosterman, M.A., and Schmidt,
M.T., eds., Earth Science Investigations: Alexandria, American Geological
Institute, p. 117-126.
Cvancara, A. M., 1985, A Field Manual for the Amateur Geologist--Tools and
Activities for Exploring Our Planet: Englewood Cliffs, Prentice-Hall, 257
p.
Fazio, R. P., 1981, Urban geology: Science and Children, v. 18, no. 8, p.
14-15.
Fazio, R. P., and Nye, O., 1980, Making 'rock hounds' of 'city slickers':
The Science Teacher, v. 47, no. 2, p. 21-23.
Hannibal, J. T., and Schmidt, M. T., In press, Interpreting urban geology:
Jour. of Geological Education.
Hebrank, A. W., 1989, The geologic story of the St. Louis riverfront (a
walking tour): Missouri Department of Natural Resources, Division of Geology
and Land Survey, Special Publication 6, 46 p.
Parsons, C., 1990, Decorating with Marble, Stone and Granite: Secaucus,
Chartwell Books, 127 p.
Pennington, P., IV, and Mastie, D. F., 1984, A downtown field trip: Michigan
Earth Scientist, v. 20, no. 3, p. 12-16.
Slagle, E. S., 1982, A Tour Guide to the Building Stones of New Orleans:
New Orleans Geological Society, 68 p.
Wilson, R. L., 1979, Building Stones of Downtown Chattanooga: Published
by the author, 63 p.
Name: __________________________________
Stop 1
1. What is the name of this building?
2. Examine the outside of this building. How many colors do you see in the rock?
3. The colors are due to different minerals. In the box below, draw the rock showing the minerals. Color in the minerals.
4. How does the surface of the building feel?
Stop 2
1. What is the name of this building?
2. Examine the columns on this building.
How do the front of the columns feel?
How do the back of the columns feel?
What might have caused the difference?
| Return to Activity-Age Table |